FALSE ALARM – 2TB THICK DATASTORE SHOWS UP AS 0.00 BYTES!

vQuicky

> VMware recently released a kb article about a bug that shows a 2TB thick datastore as 0 bytes in the datastore browser. The disk shows as 0.00 bytes even on ssh and on console.

> The 2TB thick disk provisioned to the virtual machine shows as 0.00 bytes.

> All files are accessible and the disk is accessible as well. All features are supported such as storage vmotion.

> The issue is caused due to a 32 bit addressing limitation of the DU command and the datastore browser – and a VMFS 5 disk of 2TB ends up being 2,181,972,430,848 bytes.

> Work around is to either convert the disk to thin by storage vmotion OR have the datastore to 1.95 or 1.99 TB.

inDepth

Turns out VMware has some bugs that it needs to take care of. The most recent that is reported is the disk space reporting on a 2TB thick provisioned datastore presented to a virtual machine. Now turns out that the du command on the shell and the datastore browser cannot read any bytes beyond the 32 bit addressing limitation. Now a VMFS5 thick disk 2TB datastore ends up being 2,181,972,430,848 bytes.

This errors out and datastore browser and du command on ssh reports it as 0.00 bytes throwing YOU into panic mode.

Apparently this does not affect any data on the disk nor will this prevent us from performing any operations on the disk such as storage vmotion. This ends up being more of a reporting issue and could throw some of the end users who have read-only access to their vms over the vsphere web-client into panic mode.

Obviously, a quick fix would be to NOT have a disk presented as 2TB and instead having the disk presented as 1.97TB may be. Another alternative would be to pick the provisioning as thin format – but that can add management risks and overhead. My suggestion would be to have a thick disk of 1.95 TB.

Also remember, althought the datastore can be as large as 64TB, the disk presented to the vm can only be 2TB at maximum. You cannot have one single 64TB disk presented to the VM.

Here is the KB article in case you want to read.

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